The present disclosure relates to a sheet loading unit including a pair of cursors for positioning sheets in a width direction, and a pinion engaging with racks of the cursors so as to rotate, and to a sheet transport device and an image forming apparatus including the same.
Conventionally, there is widely used a sheet loading unit equipped with a pair of cursors including racks moving in the width direction of a paper sheet (sheet) and positioning portions for positioning the paper sheet in the width direction, and a pinion engaging with the pair of racks so as to rotates when the racks move. The racks and the pinion are disposed between a sheet loading plate on which the paper sheets are loaded and a main body disposed below the sheet loading plate, and the positioning portions of the cursors are disposed above the sheet loading plate.
In an assembling process of this sheet loading unit, the sheet loading plate is placed in a turned over state (upside down), and the pair of racks are placed on the sheet loading plate. Then, the pinion is engaged with the pair of racks and is attached to a shaft of the sheet loading plate. After that, the sheet loading plate, the racks and the pinion are turned over and are placed and attached onto the main body. In order to prevent the pinion from dropping off in this case, a snap fit structure for preventing drop-off of the pinion is provided to the shaft of the sheet loading plate in the conventional sheet loading unit.